Usefulness of diffusion tensor imaging in patients who showed sustained unexplainable clinical symptom of torticollis.

To investigate corticospinal tract (CST) status using diffusion tensor imaging (DTI) in patients who had clinical symptom of torticollis but no definite cause of sustained symptom of torticollis. We evaluated 10 patients with sustained torticollis and 12 age-matched control subjects. All patients showed no specific fibromatosis coli findings on neck sonography. Even after intensive manual therapy, there was no improvement of clinical symptom of torticollis. DTI was performed using 1.5 T with a synergy-L Sensitivity Encoding (SENSE) head coil. Fractional anisotropy and apparent diffusion coefficient were measured using the region of interest method, and diffusion tensor tractography was conducted. We estimated the asymmetric anisotropic index (AA) and asymmetric mean diffusivity index (AD) to evaluate the asymmetry between right and left CSTs. All patients showed only torticollis symptom but no definite hemiplegic pattern on their extremities at initial evaluation. DTT, which was performed to reveal the reason of sustained asymmetric postural symptom showed hemiplegic pattern. The results of DTT corresponded to the delayed hemiplegic symptoms, which were found in the patients at second evaluation. AA and AD values between patients and control group were significantly different. Torticollis is usually caused by fibromatosis coli, but may be one of the symptoms of hemiplegia. DTI may be an additional technique for the early detection of hemiplegia in patients with sustained symptoms of unexplainable postural torticollis.